This is a text for an introductory astronomy course. One of the main goals is to provide a broad enough and deep enough background in astronomy so the student will be able to follow current developments in astronomy years after they complete the course. This book presumes that most of its readers are not science majors and that they probably have not had a college-level science or mathematics course. The book provides a complete description of current astronomical knowledge, neither at an extreme technical level nor at a level that fails to communicate the quantitative nature of physical science. Finally, the historical development of astronomy is emphasized to show that astronomy, like other sciences, advances through the efforts of many scientists, and to show how present ideas have been developed.